I get a lot of him im him him him him him when dictating. It could be my breathing. I'm using Dragon 15.30.000.06 him him him him him him him. I just turned it of. I'm sure it a setting but where? My mic is a Plantronics Savi W740 series, which I have used for years.

Him him him is interference. This could be a grounding issue or something as simple as your mouth being too close to the microphone element. If you're using a headset, try moving the microphone element off to the side and even slightly below your lower lip. If this doesn't fix the problem, open DragonPad, dictate a few words and say play that; to listen for possible interference.

Using DPI or a third party program, define multiple "him"'s as nothing. In Vocola, I have global commands:
him him = "";
him him him = "";
him him him him = "";
and him = "";
him him him him him = "";
him him him him him him = "";
him him him him him him him = "";

Although microphone placement might account for the behaviour, most times I've experienced or seen the "him him him" problem, the source was the sound system: a frayed wire, an old microphone, a failing USB port, a USB hub being shared with other hardware, etc.

You say you've been using the same microphone for years. If it is showing signs of wear and tear, this might be the moment to consider replacing it. But try the "free" solutions first, like double-checking your micrphone placement, plugging the microphone into a different USB port, ensuring that the Savi is the microphone that Dragon is seeing (rather than the integrated microphone in your computer), and re-running the Audio Setup Wizard.